#include <iostream>
#include <vector>

using namespace std;

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) {
        vector<vector<int>> ret;
        int n = nums.size();
        for(int st = 0;st < (1 << n);st++)
        {
            vector<int> tmp;
            for(int i = 0;i < n ;i++)
            {
                if((st >> i) & 1)
                {
                    tmp.push_back(nums[i]);
                }
            }
            ret.push_back(tmp);
        }
        return ret;
    }
};